The aim of this study was to examine the relationship between teachers' teaching-learning conceptions and their curriculum fidelity level. The study embraced "relational survey model", which is one of the quantitative research approaches. The study group consisted of teachers (n = 215) working in public high schools in the province of Nigde, Turkey. "Teaching-learning conceptions" and "curriculum fidelity" scales were used for data collection. Pearson product-moment correlation analysis and multiple regression analysis techniques were used to analyze the data. The findings indicated that while there is a positive significant relationship between constructivist teaching-learning conceptions and curriculum fidelity level of teachers (r = 0.232, p < 0.05), there is no significant relationship between traditional teaching-learning conception and curriculum fidelity level (r = 0.019, p > 0.05). According to the results of the multiple regression analysis, it was observed that teaching-learning conceptions significantly predict curriculum fidelity (R = .239, R[superscript 2] = 0.057, p < 0.05). In addition, it was seen that constructivist teaching-learning conception was a significant predictor of curriculum fidelity (ß = 0.242), unlike traditional teaching-learning conception (ß = 0.058). Considering these findings, it could be stated that teachers with constructivist teaching-learning conception have a higher level of curriculum fidelity.